The iPhone’s Mail app is convenient and simple to use, but there’s no “select all” button that allows you to delete all your email at once.
There is a workaround to select all your email on an iPhone — while in Edit mode, select a message, hold the move button, and then unselect the email.
After this, you can move them to the trash. If you store email in several folders, you can repeat this process for every folder you want to empty to delete all of your emails in the app.
If you’ve ever wanted to delete all the email on your iPhone in one fell swoop, you might have been frustrated that there’s no “select all” button to let you trash everything at once.
Thankfully, even though there’s no obvious way to do it, you can still delete all the email on your iPhone with a few taps.
There’s one caveat: This process works a folder at a time. So while you can delete your entire Inbox at once, if you store email in a lot of subfolders, you may need to delete the contents of each folder one at a time.
How to delete all of your emails from folders of your iPhone’s Mail app
1. Open the Mail app.
2. Open the folder that you want to flush out — this can be your inbox, a folder within one of your email accounts, or even the “All Inboxes” view that combines all the inboxes on your phone.
3. Tap Edit at the top of the screen.
4. Tap the first item in the folder.
5. Tap and hold “move” at the bottom of the screen.
6. While you continue to hold “Move,” tap the selected email message again to deselect it. Let go of “Move.”
7. After a moment, the view should change to show all the folders in the account, with a message at the top indicating how many messages are selected. The more messages you are selecting, the longer this may take — a few emails should be almost instantaneous, while thousands of emails might take a minute.
8. Tap on the folder called “Trash.”
All of the selected emails will move to the trash, which you can then clear.